Phosphorus is fairly common chemical element on our planet.Its name translates as "luminous", because in pure form it glows brightly in the dark.Open this item was quite by accident, alchemist Henning Brand, as he tried to extract gold from urine.Since phosphorus is the first element that alchemists were able to get through their experiments.
Characteristics of phosphorus
It is chemically very active, so naturally it can be found only in the form of minerals - compounds with other elements, of which there are 190 species.The most important connection - it's calcium phosphate (mineral apatite).Now there are many varieties of apatite, the most common of which is fluorapatite.From apatite composed of different types of sedimentary rocks - phosphates.
phosphorus for living organisms is very important as a part of both vegetable and animal protein in the form of different compounds.
In plants, this element is contained mostly proteins in the seed and in animals - various blood proteins, milk, brain cells and nerve tissues.Large amount of phosphorus contained in the form of calcium phosphate in bones of vertebrates.
Phosphorus exists in three allotropic modifications: white phosphorus, red and black.Let's look at them in more detail.
White phosphorus can be obtained rapidly cool the vapors.Then formed a crystalline solid, which is in its pure form is absolutely colorless and transparent.White phosphorus, intended for sale, usually painted in a slightly yellowish color and its appearance is very similar to wax.In this cold material becomes fragile, and at a temperature above 15 degrees becomes soft and can be easily cut with a knife.
In water, white phosphorus is not dissolved, but responds well to organic solvents.In air, it quickly oxidizes (starts to burn) and still glows in the dark.Actually, the idea of the luminous substance and detective stories of the Hound of the Baskervilles connected with white phosphorus.It is a potent poison that lethal even in small doses.
Red phosphorus - is solid dark red color, which in its properties is very different from that described above.It is oxidized in air slowly, in the dark, lit, lit only by heating in an organic solvent solution thereof is impossible, and it is not poisonous.With strong heating, in which the absence of air, it does not melt, turns to steam, which, on cooling, it turns white phosphorus.When burning both elements phosphorus oxide is formed, which proves the presence in their part of the same element.In other words, they are formed by a single element - phosphorus - and are an allotropic modifications.
Black phosphorus is obtained from white at 200 degrees Celsius under high pressure.It has a layered structure, a metallic luster and appearance similar to graphite.Of all types of solid substances it is the least active.
Application phosphorus
Modern production of phosphorus - about one million tonnes per year.Major producers: the United States, the Netherlands, Canada, Germany.
The bulk of the extracted phosphorus costs of obtaining thermal phosphoric acid, which is used in the manufacture of fertilizers and phosphates.White phosphorus is used as an incendiary and smoke-producing agent, including for tracer ammunition.
Red is used to make incendiary surface of a matchbox, and in the production of incandescent light bulbs, he acts as a getter.
Phosphorus found its application in industry.It is used as an additive to produce doped alloys, solders, soft magnetic and bearing alloys.
